Miniature circuitry and inductive components and methods for manufacturing same

Abstract

Miniature circuitry and inductor components in which multiple levels of printed circuitry are formed on each side of a support panel, typically a printed circuit board or rigid flex. Magnetic members are embedded in one or more cavities in said support panel. Electrical connection between the plural levels of circuitry and multiple windings around the magnetic members are provided by plural plated through hole conductors. Small through hole openings accommodate a plurality of the plated through hole conductors since each is insulated from the others by a very thin layer of vacuum deposited organic layer such as parylene having a high dielectric strength. Adhesion of this plated copper to the organic layer is provided by first applying an adhesive promotor to the surface of the organic layer followed by the vacuum deposition of the organic layer.

What is claimed is: 
     
       1. A miniature magnetic device comprising:
 a support member having a cavity formed therein, 
 a magnetic member embedded in said cavity such that said magnetic member is substantially contained within said cavity, 
 a first and second printed circuit formed on respectively opposite sides of said support member, 
 a first plurality of plated through holes in said support member around the outside perimeter of said cavity of said toroidal cavity, 
 a second plurality of plated through holes in said support member around the inside perimeter of said cavity, 
 said first printed circuit including connecting respective first and second plated through holes, 
 said second printed circuit including connecting respective first and second plated through holes, 
 a third plurality of plated through holes in the same holes as said first plurality of plated through holes, said first and third plurality of through holes being electrically insulated from each other by vacuum depositing a thin layer of parylene followed by treating the outside surface of the parylene coated holes with an adhesion promoter, 
 a fourth plurality of plated through holes in the same holes as said second plurality of plated through holes, said second and fourth plated through holes being electrically insulated from each other by the vacuum deposited thin layer at parylene, 
 third and fourth printed circuits formed in respective layers over the layers of said first and second printed circuits with an insulated layer therebetween, 
 said third printed circuit including connecting respective third and fourth plated through holes, 
 said fourth printed circuit including connecting respective third and fourth through holes, 
 said plated through holes and printed circuit connections forming primary and secondary windings of said miniature magnetic device. 
 
     
     
       2. A miniature magnetic device comprising:
 a support member having a toroid shaped cavity formed therein; 
 a magnetic member embedded in said cavity such that said member is substantially contained within said cavity, 
 first and second printed circuits formed on respectively opposite sides of said support members, 
 a first plurality of plated through holes in said support member around the outside perimeter of said cavity, 
 a second plurality of plated through holes in said support member around the inside perimeter of said cavity, 
 said first printed circuit including connecting respective first and second plated through holes, 
 said second printed circuit including connecting respective first and second plated through holes, 
 a third plurality of plated through holes in the same holes as said first plurality of plated through holes, said first and third plurality of through holes being electrically insulated from each other by a thin vacuum deposited layer of parylene, 
 a fourth plurality of plated through holes in the same holes as said second plurality of plated through holes, said second and fourth plated through holes being electrically insulated from each other by a thin vacuum deposited layer of parylene, 
 third and fourth printed circuits formed in respective layers over the layers of said first and second printed circuit with an insulated layer therebetween, 
 said third printed circuit including connecting respective third and fourth plated through holes, 
 said fourth printed circuit including connecting respective third and fourth through holes, 
 said plated through holes and printed circuit connections forming primary and secondary windings of said miniature magnetic device. 
 
     
     
       3. A miniature magnetic device comprising:
 a support member having a toroid shaped cavity formed therein, 
 a magnetic member having a shape similar to said cavity, said magnetic member embedded in said cavity such that said magnetic member is substantially contained within said cavity, 
 first and second printed circuits formed on respectively opposite sides of said support member, 
 a first plurality of plated through holes in said support member around the outside perimeter of said shaped cavity, 
 a second plurality of plated through holes in said support member around the inside perimeter of said shaped cavity, 
 said first printed circuit including connecting respective first and second plated through holes, 
 said second printed circuit including connecting respective first and second plated through holes, 
 a third plurality of plated through holes in the same holes as said first plurality of plated through holes, said first and third plurality of through holes being electrically insulated from each other by having a substantially pin-hole free insulating layer having a thickness in the range of about 0.5 mil to 3 mil and having a voltage breakdown guard band in the range of about 5600 to 15,000 volts per mil per unit of thickness, 
 a fourth plurality of plated through holes in the same holes as said second plurality of plated through holes, said second and fourth plated through holes being electrically insulated from each other by substantially said pin-hole free insulating layer, 
 third and fourth printed circuit formed in respective layers over the layers of said first and second printed circuits with an insulated layer therebetween, 
 said third printed circuit including connecting respective third and fourth plated through holes, 
 said fourth printed circuit including connecting respective third and fourth through holes, 
 said plated through holes and printed circuit connections forming primary and secondary windings of said miniature transformers. 
 
     
     
       4. A miniature magnetic device having a base member,
 a cavity formed in said base, 
 a magnetic member located in said cavity, said member providing a magnetic core of said magnetic device, 
 a plurality of openings in said base, 
 a plurality of plated through hole conductors formed in said through hole openings, each of said conductors being respectively electrically insulated from another plated through hole conductor in the same hole by a thin vacuum deposited polymer film, 
 said plated through hole conductors providing windings of said magnetic device. 
 
     
     
       5. The magnetic device of  claim 4 , wherein said cavity has a substantially toroidal configuration. 
     
     
       6. The magnetic device of  claim 5 , wherein said magnetic member has a substantially toroidal configuration similar to said cavity. 
     
     
       7. The magnetic device of  claim 4 , wherein said cavity has a substantially rectangular configuration. 
     
     
       8. The magnetic device of  claim 7 , wherein said magnetic member has a substantially rectangular configuration similar to said cavity. 
     
     
       9. The magnetic device of  claim 4 , wherein said magnetic member has a substantially E-shaped configuration. 
     
     
       10. The magnetic device of  claim 4 , wherein said magnetic member has substantially the shape of an oblong toroid. 
     
     
       11. The magnetic device of  claim 4 , wherein said magnetic member has an asymmetric configuration. 
     
     
       12. The magnetic device of  claim 4  wherein said magnetic member is shaped to fit into the housing of a miniature electronic apparatus. 
     
     
       13. The magnetic device of  claim 4  wherein said magnetic member is a ferrite. 
     
     
       14. The magnetic device of  claim 13  wherein said ferrite is a polycrystalline ceramic soft ferrite. 
     
     
       15. The magnetic device of  claim 4  wherein said magnetic member is a metal alloy. 
     
     
       16. The magnetic device of  claim 4  wherein said magnetic member is crystalline nickel-iron amorphous cobalt based alloy. 
     
     
       17. The magnetic device of  claim 4 , wherein said openings in said base are in said support member proximate to a wall of said magnetic member. 
     
     
       18. The magnetic device of  claim 4 , having through holes extending through the body of said magnetic member. 
     
     
       19. The magnetic device of  claim 4 , wherein said base member is formed from a printed circuit board. 
     
     
       20. The magnetic device of  claim 4 , wherein said base member is formed of flex circuit. 
     
     
       21. The magnetic device of  claim 4 , wherein said cavity is an opening substantially entirely through said base member. 
     
     
       22. The magnetic device of  claim 4 , wherein said cavity is formed partially through the wall of said base member to leave a seat of the bottom of the cavity. 
     
     
       23. The magnetic device of  claim 4  wherein said thin vacuum deposited film is parylene.